Method of making aldehyde-amines



Jan. 31, 1933. I W. L. S EMON' Er A L v I 1,895,945 METHOD OF MAKING ALDEHYDE MINES 7 Filed Dec. 20. 1928 m m: Z7/b'a .Z Evan 15/0517 Patented Jan. 31, 193 3 UNITED STATES PATENT orFrcE WALDO L. SE'MON, OF CUYAHOGA FALLS, AND ARTHUR W. SLOAN, OF AKRON, OHIO, ASSIGNORS TO THE B. F.' GOODRIGH COMI'ANY, OF NEW YORK, N. Y., A. COR- PORATION OF NEW YORK METHOD OF MAKING- ALDEHYDE-AM-INES Application. filed December 20, 1928. Serial No. 327,309.

This invention relatesto the art of manu- .facturing organic chemicals, and has for its object to provide an improved method of manufacturing aldehyde-amines.

The reaction products of aldehydes and amines have found very extensive use as vulcanization accelerators or as age-resisters in rubber compositions. "For. example, ace-taldehyde-aniline, butyraldehyde-p-amino-dimethylaniline, heptaldehyde-aniline, acetaldehyde-o-toluidine, crotonaldeh tie-aniline,-

-with an inlet 22 for the introduction of one of the reacting materials and a nozzle 23 q 5 etc., are excellent accelerators o vulcanization, whereas aldol-al ha-naphthylamine, butyraldehyde-alpha-nap thylamine, etc., are

very effective age-resisters for rubber. Such aldehyde-amines. are most I commonly pre-' pared by mixing the aldehyde and the amine 1n equimolecular proportions, or whatever other proportions may befound desirable, and heatin the mixture untilthe reaction has procee ed and'water has been eliminated. The molten aldehyde-amine is then drawn outof the reaction vessel and allowed to cool. Such batch methods of manufacture require the "use of large steam-jacketed kettles and require the employment of considerable labor to supervise and conduct the operations. This invention, in brief, consists in reacting aldehydes with amines continuously in a suitable apparatus. The exact procedure is susceptib e of numerous variations, depending on the physical and chemical char acter of the respective aldehydes and amines, on the proportions of the materials reacted, on the temperature at which the reaction best takes place, etc. However, the essential feature is the continuousreact-ion of an alde-" hyde with an amine in a reaction tube or vessel, the product being. discharged in a continuous stream therefrom.'

An apparatus wherebytheobjectsmf this I invention maybetaccomplished is illustrated .'1n the accompanying drawing; Fig. 1 is a dlagrammatic'representation of the appara-' tus as a whole, whileIFig.'- 2 is a section on a slightly larger scalethroligh the line 2, 2 of Fig. 1. Refe'rring'to Fig. 1 of the drawing, 10 and 11 are liquid reservoirs supported in any suitiable manner as bythe frame work 12, 12.

The reservoirs are preferably e jackets 13, which may be supp whereby. the other material is injected into and mixed with'the first. The admixture of baflies 24, 24. The baflies maybe arranged in airs as indicated in the sectionalview of i g. 2, alternate pairs being twisted in fopposite directions, so as to change the direction of flow many times during the passage .of the materials through the tube. 'The re action tube is surrounded by a fluid jacket 25 by means of which it may conveniently be pipes 15, 15 equipped uipped with ied through the pipes 14, 14 with a cooling or heating. p

the two materials during" their passage through the tube 21 is ensured by spiral maintained at any desired temperature, and y the end is bent in a gooseneck 26 to prevent the reacted materials from running out the end of the tube leaving it only partially filled. The mixture flowing from the gooseneck may be dried by allowing it to flow .over a heated surface, such as the steam plate 27, heated, by admitting steam to its ollow interior. The finished product is drained therefrom into suitable receptacles such as the can ,or drum 28.

The operation of the apparatus will bedescribed with reference to the manufacture of the aldehyde-amine product known as aldol-naphthylamine, and extensively employed as an age-resister or antioxidant in rubber. although it is to be understood that in the same or a similar manner.

The reservoir 10 is charged with solid alpha-naphthylamine,'and the reservoir 11 with aldol. A small amount of acid, say

any other aldehyde-amine may be prepared 0:1% 'of concentrated hydrochloric acid is added to the aldol in reservoir 11 and thoroughly admixed therewith. Steam is ad mitted through the pipes 14, 14 to the jackets 13, 13 surroundin the reservoirs, until the alpha-naphthylamme has melted and the liquid in both reservoirs has attained a temperature of from 50 to 80 C. The valves l6,' l6-are then opened and the pumpsl'? and 18 started, the rate of operation of the pumps being soregulated that while ump l7 discharges 143 pounds of molten a phanaphthylamine, pump 18 discharges- 88 pounds'of aldol; that is, that they discharge equimolecular proportions of the two substances. The two liquids discharged by the pumps flow into and through the reaction vessel 20, where they are thoroughly admixed. Steam is also admitted to the jacket of the reaction vessel under sufiicient pressure to maintain the reaction mixture at a temperature well above 100 C. At this temperature the reaction of the aldehyde and the amine takes place very, rapidly, water being eliminated in the course of the reaction between the aldehyde and amine. Since the reaction is exothermic, the temperature of the product issuing. from the reaction vessel will usually be considerably higher than even the temperature of the steam jacket. A final temperature of about 180 has been found satisfactory. The water formed by the re action is present in the product in a finely divided form, butis evaporated therefrom as the product flows over the steam heated plate 27, where a large surface is exposed to the atmosphere. The finished dried product is then collected in suitable receptacles such asv the thin-walled can 28 and is allowed to cool. The finished aldol-alpha-naphthylamine is a brittle, resinous. amber-colored solid, which softens at slightly elevated temperatures and becomes fluid at about C. 4 In the process described .above, a small amount of a mineral acid was added to the' aldol, for it has been-found that the reaction of certain aldehydes with amines is greatly.

accelerated by the presence of a small proportion of such an acid, which appears to act as a reaction catalyst. However, any other moderately strong acid, such as sulphuric acid, phosphoric acid, salicylic acid, or even salts of strong acids with weak bases, or other substances possessing a definite acid reaction, may be substituted for the hydrochloric acid mentioned above. In many cases the natural a cidity of the aldol or other aldehyde is suffic1ent to catalyze the reaction, but in the total absence of acid,'as when the aldol is neutraliz'ed by a'slight excess of sodium bicarbonate, the reaction does not take place. This propert may be made useful, as further indicated" low.

It-has' been found "that a product substantially identical with that described above maybe prepared by substituting acetaldehyde for the aldol. It is known that aldol is a condensation product, two molecuhes ofacetaldehyde combining to form one mol of aldol. Apparently 'the same condensation may e ually well be employed.- "The paraldehyde ecomposes readily into acetaldehydc.

which undergoes the aldol condensation and reacts with the amine, with the formation again of the resinous aldol-alpha'- naphthylamine. It was also found that, instead of reacting aldol and alphasnaphthylamine with the elimination oftwo molecules of water, a molecule of water may be eliminated from the aldolbefore its reaction, the product, crojtonaldehyde, reacting with alpha-naphthyh amine to form a final product very similar to that secured with aldol itself. It is evident,

then, that it is immaterial whether the reac-' tion is carried out with acetaldehyde or any of its. simpler derivatives, namely paraldehyde, aldol, or crotonaldehyde, the products formed from all these substances being substantially identical. The choice astowhich substance is selected in a given case is gov- 'erned ,by considerations of convenience.

Acetaldehyde has the disadvantage of being 1 i very volat le, aldol is a viscous syrupy liquid, and crotonaldehyde has an exceedingly pungent and disagreeable odor, while paraldehyde is a, fairly stable mobile liquid with a fairly high boiling point.

The reaction need not be carried out at high temperatures since aldehyde and amines .react at room temperature. Of course the reaction at room temperatures takes much longer, so that it is not usually convenient to carry it to completion in a reaction chamber at a low temperature. However, the process of this invention may be employed at a low temperature it desiredr Insuch a case the v aldehyde and amine are not heated any more thanmay be necessar to effect the admixture. The alpha-nap thylamme, for example is heated onl a few degrees above its eltin'gpoinhwhile the aldol is heated only very little or not at all. The two ingredients are then mixed as hereinabove described, except that the reaction vessel is cooled instead of heated, the mixture thus being sufiiciently j cooled that substantially no reaction takes place in the reaction vessel. The mixture of the unreacted aldol and a1 ha-naphthylamine is drawn into cans, pre erably conical in shape so that the contents may readily be removed, and allowed to stand at room temperatures for a day or two. As the reaction proceeds water separates out in minute droplets throughout the'mass and the mixture solidifies. Finally the cans are inverted and the cake knocked'out, ground and dried.

It is obvious that other proportions of thereactingmaterials may be employed; for example, two or more molecular proportions of aldehyde" may be reacted with one molecular proportion vof the amine. Furthermore, the ingredients may be mixed in a different order from that described above. 'Thus if the reaction is carried out at high temperatures, the acid catalyst may be mlxed with the amine instead of with the aldehyde and the tworeacted as described above. 'Or, if desired, the aldehyde may be neutralized with a slight excess of sodium bicarbonate or other base and -mixed with the amine in one reservoir, no reaction taking place until acid is added thereto, while a dilute acid solution is prepared in, the other reservoir. The mixture of the unreacted aldehyde and amine is then mixed with the acid in the heated reaction vessel, the reaction taking placealmost instantaneously. If, on the other hand,'it is desired to allow the reaction to proceed at a low temperature'over a considerable time, the aldehyde-amine mixture and the acid are continuously mixed in'the well-cooled reaction vessel, the product being drawn into cans and allowedto stand until the reaction is, complete.

The react-ion may even be carried .out in solution. one or both of the reacting materials being dissolved, in water, alcohol, or other suitable solvent. In this case it will usually be necessary to employ a larger proportion of acid to catalyze the reaction, sometimes even as much as a molecule of acid for each molecule of amine. The product is precipitated in the form of fine particles suspended in the acid solution. The solution must be neutralized and the aldehyde-amine'filtered I oil and dried. V

If it is intended to prepare other ageresisting aldehyde-amines than aldol-alphanaphthylamine, or even ifit is desired to prepare accelerating aldehyde-amines, the

' method of this invention may be employed,

with such minor modifications as may be required by the physical properties of the respective reacting'materials, their melting points, boiling points, viscosity, etc., or by their chemical properties such astheir reactivity, etc. Thus the following aldehydeamines or the corresponding poly-aldehydeamines may very readily and economically be prepared by such a continuous process:

acetaldehyde-aniline. furfuraldehyde-orthotoluidine, butyraldehydemniline, butyralde liyde-alpha-naphthylamine.

heptaldehydeanlline, butyraldehyde-butylamine, acet'aldepiperidine, etc.

lVhile we have herein disclosed with considerable particularity certain preferred manners of performing our invention, we do not thereby desireor intend to limit ourselves solely thereto, for, as hitherto stated, the procedure may be modified, the precise proportions of the materials utilized may be varied hyde-p-amino-diphenylamine, formaldehyde claims.

and other materials having equivalent chemical properties may be employed if desired without departing from the spirit and scope of the invention as defined in the appended WVe claim: 1. The method of manufacturing aldehydeamines whichcomprises continuousl admix-- ing an aldehyde and an amine 1n fixed, predetermined proportions, and causing the reaciion thereof. p

2. The method of manufacturing aldehydeamines which comprises continuously admixing an aliphatic aldehyde and anamine in fixed, predetermined proportions, and causing the reaction thereof.

3. The method of manufacturing aldehyde- I amines which comprises. continuously. admixing an aliphatic aldehyde and an aromatic amine in xed, predetermined proportions, and causingthe reaction thereof. 7

4. The method of manufacturing aldehydeamines which comprises continuously admixing an aliphatic aldehyde and a primary amines which comprises continuously ad'mixing an aliphatic aldehyde and a primary aromatic amine-in fixed, predetermined proportions in the presence of a small proportion of an'acid catalyst and heating the mixture toits reaction 'tem rature.

7 The method 0 manufacturing aldehydeamines which comprises continuously separately heating'an aliphatic aldehyde and a primary aromatic amine, and mixing. them in the presence of .a small proportion of an acid catalyst in a reaction vessel heated to their reaction temperature, and continuously withdrawing the product.- I

- 8. The methodof manufacturing aldehyde- V amines which comprises continuously admix- .ing an aliphatic aldehyde and a naphthylamine; subjecting the mixture to a. moderately elevated temperature, and continuously withdrawing the product.

9. The method of manufacturingalde hyde-amines which comprises continuously admixing a naphthylamine and a substance selected from the class consisting of acetaldehyde, paraldehyde, aldol. and crotonaldehyde. in fixed, predetermined proportions.

.and subjecting the mixture to a moderately elevated temperature.

hyde-amines which comprises continuously admixing alpha-naphthylamine with a. substance selected from the class'consisting of acetaldehyde, paraldehyde, aldol, and croton: aldehyde in a reaction vessel heated'to a tem-' -perature exceeding 100 C. continuously withdrawing the product.

12. The method of manufacturing aldehyde-amines which comprises continuously admixing aldol and alpha-naphthylamine in,

fixed, predetermined proportions, and causing the reaction thereof.

13. The method of manufacturing aldehyde-amines which comprises continuously admixing aldol, alpha-naphthylamine, and a small proportion of a strong acid catalyst in fixed, predetermined proportions, and causing the reaction thereof.

14. The method of manufacturing aldehyde-amines which comprises continuously admixing aldol and alpha-naphthylamine, subjecting the mixture to a moderately elevated temperature, and continuously withdrawing the product.

15. The method of manufacturing aldehyde-amines which comprises continuously admixing aldol, alpha-naphthylamine, and a small proportion of a strong acid catalyst, subjecting the mixture to a moderately elevated'temperature, and continuously withdrawing the product. p

16. The method of manufacturing aldehyde-amines which comprises continuously admixing aldol, alpha-naphthylamine, and a small proportion ofa strong acid catalyst, heating the mixture. to a reacting temperadrawing the product, and evaporating the ,mixture to stand until the reaction is'suh stantially complete, and comminuting and drying the product. I,

20..The method of manufacturing aldehyde-amines which comprises continuously mixing aldol and alpha-naphthylamine at substantially room temperature in thegpresence of a small proportion of anacid catalyst, continuously withdrawing the mixture,

allowing it to stand until the reaction is substantially com lete, and comminuting and drying the pro uct.

In witness whereof we have hereunto set our hands this 8th day of December, 1928.

' v WALDO L. SEMON.

ARTHUR W. SLOAN.

tlire, continuously withdrawingtheproduct, I

and evaporating the water therefrom.

17. The methodof manufacturing alde; hyde-amines which comprises continuously admixing substantially equimolecular proportions of aldol and alpha-naphthylamine at a temperature above 100 C. in the presence of a small proportion of a strong acid catalyst, continuously with drawing the product,

' and evaporating the water contained in the product.

18. The methodof manufacturing. aldehyde-amines which comprises separately heating alpha-naphthylamine and aldol contaming a small proportion of a strong acid catalyst, admixing them continuously in substantially equimolecular proportions in a heated reaction vessel, continuously with- 

